My rpbs were only "mean when feeding" which for that tank meant whenever the lid was up, they were tiny when I sterted with the divider trick so the only people who got bit going for the silver dollars in the tank. The bet was if they grabbed one with their hand and brought it out they could keep it, they only got one try, over a couple of years several tried one got a dollar and all got bit, at the end they were around 9"